Genetic and genomic analysis of Ras signaling in colorectal cancer progression

描述(申请人提供)：我的主要目标是了解K-RAS的突变激活是如何在结直肠癌恶性进展的早期诱导高度不典型增生的。我的工作假设是，突变的K-RAS信号通过B-RAF激酶抑制良性结肠肿瘤细胞的分化。建议的研究包括旨在从机制上深入了解已知的RAS效应通路的有针对性的研究，以及旨在识别K-RAS信号的新效应器的探索性研究。我提出三个具体目标： 目的1.分析激活K-ras、H-ras和N-ras对肠上皮细胞表型的影响。 目的2.确定候选效应通路与K-ras诱导的肿瘤进展的相关性。 目的3.鉴定突变激活的K-ras新的信号效应因子。 我的研究将利用体外和体内的实验系统，即人类结直肠癌细胞系和基因工程小鼠。在这些互补系统中进行的平行研究将对K-RAS信号的致癌特性产生最大的洞察力。为了成功地完成特定的目标，我将使用小分子抑制剂、全基因组磷蛋白质组分析和新兴的shRNA技术来剖析致癌K-RAS促进肿瘤进展所需的信号通路。最后，我相信，以RAS信号通路为靶点的治疗将是对抗结直肠癌恶性进展的有力手段。 与公众健康相关：2005年1月，美国癌症协会宣布，癌症已取代心脏病成为美国的头号死因。在这个国家，仅结直肠癌一项每年就造成50,000多人死亡。尽管我们已经了解了结直肠癌的分子发病机制，但在过去的二十年里，这种疾病的死亡率一直保持不变。通过我对K-RAS癌基因的功能研究，我的目标是为根除结肠癌的新疗法确定分子靶点。

DESCRIPTION (provided by applicant): My primary goal is to understand how mutational activation of K-RAS induces high grade dysplasia early during the malignant progression of colorectal cancer. My working hypothesis is that mutant K-RAS signals through the B-RAF kinase to suppress the differentiation of benign colonic tumor cells. The proposed studies include targeted investigations aimed at gaining mechanistic insight into known RAS effector pathways and exploratory studies aimed at identifying novel effectors of K-RAS signaling. I propose three specific aims: Aim 1. Analyze the phenotypic effects on the intestinal epithelium of activating K-ras, H-ras, or N-ras. Aim 2. Determine the relevance of candidate effector pathways to K-ras-induced tumor progression. Aim 3. Identify novel signaling effectors of mutationally activated K-ras. My studies will utilize both in vitro and in vivo experimental systems, namely human colorectal cancer cell lines and genetically engineered mice. Parallel studies conducted in these complementary systems will yield the greatest amount of insight into the oncogenic properties of K-RAS signaling. To successfully complete the Specific Aims, I will use small molecule inhibitors, genome-wide phosphoproteomic analysis, and emerging shRNA technology to dissect the signaling pathways that are required for oncogenic K-RAS to promote tumor progression. In the end, I am confident that therapeutic targeting of the RAS signaling pathway will represent a powerful means of fighting the malignant progression of colorectal cancer. Relevance to public health: In January, 2005 the American Cancer Society announced that cancer has replaced heart disease as the number one cause of death in the United States. Colorectal cancer alone accounts for more than 50,000 deaths per year in this country. Despite all that we have learned about the molecular pathogenesis of colorectal cancer, mortality due to this disease has remained constant over the past twenty years. Through my functional studies of the K-RAS oncogene, I aim to identify molecular targets for novel therapeutics that will eradicate colon cancer.